A native app that converts video, audio, images, documents and discs.
Built in Rust · egui GUI · ffmpeg and yt-dlp included · Nothing to download after install
- One window, every format — video, audio, image, document, disc/ISO and utilities all in one place
- Right-click to convert — "Convert with FMX" in your file manager turns a selection into MP4, MP3, JPG, PDF and more in one click (details)
- Zero setup — ffmpeg, ffprobe and yt-dlp ship inside every package; FMX never downloads programs after install
- Safe auto-updates — every release file is Ed25519-signed; unsigned or tampered files are refused
- Parallel queue — jobs run side by side with live progress, cancel and retry; a sound, a notification, opening the folder or shutting down when everything is done
- Light & dark theme — follows system preference; smooth hover/press animations; "Reduce motion" option
- 5 languages — English, Spanish, French, German and Hebrew, with a fully mirrored right-to-left layout for Hebrew
- Drag & drop everywhere — files, folders and links; one FMX window takes everything you open
- Easy to troubleshoot — a log file, a debug-logging switch and crash reports (details)
Video
MP4 (H.264 · H.265) · MKV · WebM · MOV · AVI · FLV · WMV · MPG · VOB · TS · OGV · 3GP · SWF · GIF · Animated WebP
Mobile presets: iPhone · iPad · Android · PSP · PS Vita · Xbox · Smart TV · YouTube · WhatsApp
Output settings: codec (H.264 / H.265 / AV1 / VP9) · NVENC / Quick Sync / VA-API hardware encoding · bitrate · frame rate · audio bitrate · sample rate · channels · volume
Edit panel: clip · crop · rotate · burned-in subtitles · image watermark
Clip & crop window: scrub through the video, set in/out points, drag the crop area on the live picture
Audio
MP3 · AAC · M4A · M4R ringtone · FLAC · WAV · OGG · Opus · WMA · AIFF · AC3 · MP2 · WavPack · MKA · MMF · AMR · APE
Extracts audio from any video file. Clipping and output settings included.
Image
PNG · JPG · WebP · BMP · TIFF · GIF · ICO · TGA · QOI · AVIF · JPEG XL · PCX
Join images · resize · rotate · grayscale · watermark · HEIC/AVIF inputs
Document
Images → PDF · PDF → images / TXT / HTML / Word / Excel · Office → PDF · merge / split / compress PDF · eBook → EPUB / FB2 / PDF / TXT (built in) and MOBI / AZW3 (with Calibre)
Disc / ISO
DVD → video · Blu-ray → video · Music CD → audio tracks · DVD/CD → ISO · Folder → ISO · ISO ↔ CSO (native)
Utilities
Join video · join audio · mux · mix audio · side-by-side / stacked / picture-in-picture · trim · split · crop · compress to size · remove audio · remove logo · add/extract subtitles · extract frames · rotate/flip · speed · volume · loudness normalization · repair · video downloader · screen recorder
Download the right file from the latest release:
| Platform | File |
|---|---|
| Windows 10/11 (64-bit) | fmx-<version>-windows-x64-setup.exe |
| macOS 11+ (Intel & Apple silicon) | fmx-<version>-macos-universal.dmg |
| Ubuntu / Debian (64-bit) | fmx_<version>_amd64.deb → sudo apt install ./fmx_<version>_amd64.deb |
| Other Linux (64-bit) | fmx-<version>-linux-x86_64.tar.gz → portable, just run ./fmx |
The Windows setup asks whether to add "Convert with FMX" to the right-click menu (on by default) and removes it again when you uninstall FMX. FMX installs for the current user and needs no administrator rights.
Windows note: SmartScreen may warn about an unknown publisher; choose More info → Run anyway.
macOS note: the build is not yet notarized. First launch: right-click FMX → Open.
Select files in your file manager, right-click, and choose Convert with FMX:
| Files | Conversions offered |
|---|---|
| Video (MP4, MKV, MOV, AVI, …) | MP4 · MKV · WebM · GIF · MP3 (just the audio) |
| Audio (MP3, FLAC, WAV, M4A, …) | MP3 · M4A · FLAC · WAV · Opus |
| Images (PNG, JPG, WebP, HEIC, …) | JPG · PNG · WebP · PDF (all selected images in one PDF) |
| Office (Word, Excel, PowerPoint, OpenDocument) | |
| eBooks (EPUB, FB2) | PDF · TXT · EPUB · FB2 |
| Word · TXT · Images |
FMX queues the files with your current settings and starts right away; the results are saved next to the originals, or in the output folder you chose. Open in FMX opens the files in the editor instead, to pick another tool or change options first.
| Where | How it appears |
|---|---|
| Windows 10 | In the menu of each supported file type |
| Windows 11 | Under Show more options (the new short menu only takes packaged extensions) |
| Linux | Dolphin (KDE) and Nemo (Cinnamon) in the menu; Nautilus (GNOME) and Caja (MATE) under Scripts |
On Linux FMX adds the menu the first time it starts. Turn it on or off any time in Settings → General → Right-click menu. It isn't available on macOS or in the snap.
FMX checks GitHub once a day. When a newer release is out, a dot appears on the Settings button, and Settings → Updates shows it with Update now, What's new and Skip this version; nothing pops up over your work. A release is the only thing FMX ever downloads: the bundled ffmpeg, ffprobe and yt-dlp are updated together with FMX, never on their own. Updates are safe by design:
- Only talks to this repository's GitHub releases, over HTTPS
- Never offers a downgrade, draft or pre-release
- Every file is verified against a minisign Ed25519 signature that names the exact file and version
- A file that fails the check is deleted and never run
Turn auto-check off, or hit Check now, in Settings → Updates.
Nothing needs to be installed upfront. Every release package bundles:
| Program | Source |
|---|---|
| ffmpeg + ffprobe | Pinned FFmpeg 8.1 shared build (Windows, Linux) or FFmpeg 6.1 static build (macOS, ffmpeg only), SHA-256 verified at build time |
| yt-dlp | Official standalone release (no Python needed), SHA-256 verified at build time |
They live in a tools/ folder beside fmx (/usr/lib/fmx for the .deb), and FMX
always prefers them over anything on PATH. The shared ffmpeg build lets ffmpeg and
ffprobe reuse one set of libraries, so the bundle is about half the size of two static
programs. Licenses are listed in
packaging/THIRD-PARTY-NOTICES.md.
Optional system programs that unlock extra tools when found next to the app or on PATH
(they are large desktop suites, so FMX uses your installed copy instead of bundling them):
| Helper | Unlocks | Debian/Ubuntu package |
|---|---|---|
| Poppler | PDF → images/TXT/HTML/Word/Excel, merge/split PDF | poppler-utils |
| Ghostscript | Compress PDF | ghostscript |
| Calibre | Kindle eBooks (MOBI, AZW3), and reading MOBI/PDF books | calibre |
| xorriso | Folder → ISO | xorriso |
| Monkey's Audio | APE output | monkeys-audio |
| LibreOffice | Legacy .doc/.ppt → PDF |
libreoffice |
Formats unsupported by your ffmpeg build (e.g. AMR without
libopencore_amrnb) are greyed out automatically.
On Linux the completion sound plays through pw-play, paplay or aplay, one of which every
desktop has; FMX itself needs no audio libraries.
# Fetch the same ffmpeg, ffprobe and yt-dlp a release ships, beside the dev binary
python3 packaging/fetch-bundled.py target/release/tools
# Run in development mode
cargo run --release
# Run the test suite
cargo test
# End-to-end tests (requires ffmpeg on PATH or FMX_FFMPEG set)
FMX_FFMPEG=/usr/bin/ffmpeg cargo test e2e -- --nocapture
# Hear the three built-in completion sounds
cargo test plays_each_built_in_sound -- --ignored
# Check that FMX opens its window here (exit code 0 = it works)
cargo run --release -- --self-testRust 1.89+ is required (rust-version in Cargo.toml). Building on Linux needs no extra -dev
packages (the release workflow builds on a stock Ubuntu runner).
Debug builds can save a picture of the real window, to check layouts without clicking through
them: FMX_SCREENSHOT=shot.png cargo run (see src/devshot.rs for the switches that open
Settings, the editor, a menu and so on).
| Path | What it holds |
|---|---|
src/app.rs |
The window: tools, editor, queue and Settings |
src/catalog.rs, src/plan.rs, src/jobs.rs, src/exec.rs |
Which tools exist, and how a tool and files become ffmpeg (or native) jobs |
src/shell.rs, src/instance.rs |
The right-click menu, and handing files to the one running window |
src/update.rs |
Signed self-updates |
src/diagnostics.rs, src/sound.rs |
Logs and crash reports; the completion sound |
src/i18n.rs, src/dir.rs, locales/ |
Translations, and the mirrored right-to-left layout |
vendor/epaint |
egui's text library with right-to-left text support (FMX-PATCH.md) |
packaging/ |
Bundled-tool fetching, installers and packages for each system |
Add locales/xx.json (the English file lists every string) and register it in src/i18n.rs.
If the language is written right to left, list it in RTL_LANGUAGES there too, and the whole UI
mirrors.
- Bump
versioninCargo.toml(the only place — installers and the updater read it from there). - Tag and push, with the tag matching that version:
git tag v1.2.3 && git push origin master v1.2.3 - The release workflow builds on Linux, Windows and macOS.
On Windows it also starts the real
fmx.exe(--self-test, on a machine without a GPU) and adds and removes the right-click menu; if either fails, nothing is published. It then signs every file withFMX_SIGNING_KEY, verifies it againstpackaging/update-key.pub, and publishes the release.
| Variable | Effect |
|---|---|
FMX_LANG=es|fr|de|he|en |
Override UI language (also changeable in Settings) |
FMX_LOG=<filter> |
Log level filter, e.g. debug (overrides the Settings switch) |
FMX_FFMPEG=<path> |
Force a specific ffmpeg binary |
FMX_RENDERER=glow |
Windows: use OpenGL instead of Direct3D/Vulkan |
| Option | Effect |
|---|---|
fmx --debug |
Debug logging for this run, even if FMX can't open its window |
fmx --self-test |
Open the window, draw a few frames and quit (exit code 0 = FMX works here) |
fmx --convert <target> <files…> |
Convert right away, as the right-click menu does (mp4, mkv, webm, gif, mp3, m4a, flac, wav, opus, jpg, png, webp, pdf, word, txt, images, epub, fb2) |
fmx --register-shell / --unregister-shell |
Add or remove the right-click menu for this user, then quit |
Only one FMX window runs at a time: starting FMX again (or converting from the right-click menu) hands the files to the open window.
FMX writes fmx.log (and keeps the previous run's fmx.previous.log) in its logs folder:
| System | Logs folder |
|---|---|
| Windows | %APPDATA%\fmx\logs |
| Linux | ~/.local/share/fmx/logs |
| macOS | ~/Library/Application Support/fmx/logs |
- Debug logging in Settings → General records everything FMX does; Open logs folder
takes you there. If FMX won't open at all, start it once with
fmx --debuginstead. - If FMX crashes or can't start, it saves a
crash-<time>.txtreport (what happened, where, a backtrace, the version and the system) and tells you where it is. The next start mentions it.
When reporting a problem, attach the files from the logs folder.
- Copy-protected discs: ffmpeg does not decrypt CSS (DVD) or AACS (Blu-ray).
- Screen recorder on Wayland: can only capture XWayland windows; log in to an X11 session to record the full desktop.
- No built-in player: finished files open in your default system player.
- Right-click menu: on Windows 11 it's under Show more options; there is none on macOS. Removing the
.debcan't remove the menu files in your home folder, so turn the menu off in Settings first. - Language on Windows and macOS: FMX doesn't detect the system language there yet; choose it in Settings → General.
Dual-licensed under MIT or Apache 2.0 — your choice.